A lampshade is a frustum open at both ends. Its rims have radii 17 cm and 9 cm and its slant height is 12 cm. What area of fabric covers the sloping surface? (Take \π = 3.14 .)

Question

Accepted Answer

979.68 cm². CSA = \π l (R + r) = 3.14 × 12 × (17 + 9) = 3.14 × 12 × 26 = 979.68 cm². 301.44 comes from using (R - r) instead of (R + r); 2141.48 wrongly adds both circular ends, but a lampshade open at both ends has none; 1959.36 is double, from slipping in a factor 2.

A lampshade is a frustum open at both ends. Its rims have radii 17 cm and 9 cm and its slant height is 12 cm. What area of fabric covers the sloping surface? (Take $π = 3.14.$ )

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More Class 10 Frustum of a Cone practice

A lampshade is a frustum open at both ends. Its rims have radii 17 cm and 9 cm and its slant height is 12 cm. What area of fabric covers the sloping surface? (Take π=3.14.)

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 Frustum of a Cone practice

A lampshade is a frustum open at both ends. Its rims have radii 17 cm and 9 cm and its slant height is 12 cm. What area of fabric covers the sloping surface? (Take $π = 3.14.$ )